1. Field of the Invention
The invention is directed to the cleaning shoe screens of an agricultural combine, wherein the cleaning shoe is provided with a chaffer screen and a sieve screen having readily replaceable louvers.
2. Description of the Prior Art
In agricultural combines, a harvesting platform harvests a crop and directs it through a feeder house to a threshing and separating assembly. The separating assembly is provided with a cleaning shoe for separating the chaff and unthreshed tailings from the grain.
The conventional cleaning shoe configuration comprises a chaffer screen and a sieve screen, which are of similar construction. A blower is used for directing an air blast longitudinally and upwardly to the underside of the screens. The screens are oscillated or reciprocated so that material located thereon migrates to the rear of the units. Clean grain passing through the chaffer and sieve are received by a clean grain auger which directs the grain to a storage tank. Tailings, that is unthreshed heads of grain and other heavier trash, pass through the chaffer screen and are then directed by the sieve screen to a tailings auger which returns the tailings to the threshing means. Lighter trash and chaff are directed out the rear of the combine by the air blast from the blower.
The overall structure and function of the conventional cleaning shoe is well known in the art. Such cleaning shoes can be used with conventional combines having a transverse threshing cylinder and concave, and straw walkers, or a rotary axial flow combine. The screens are provided with openings through which the grain passes. These openings can either be adjustable or fixed. The openings are defined by louvers extending laterally across the unit. Adjacent louvers overlap to define the openings by undulating structure of each louver. Sometimes individual louvers become broken and need to be replaced. Typically, either the whole chaffer screen or sieve screen would be discarded because of the difficulty in replacing the louver. The present invention is directed to a chaffer and/or sieve screen in which the louvers are readily replaceable.